The present invention relates to a piping coupling or connection device, and more particularly, to a piping connection device suitable for use in a semiconductor heat-treating apparatus, a CVD (Chemical Vapor Deposition) apparatus or the like.
A semiconductor wafer heat-treating apparatus is known for carrying out a uniform heat-treatment onto objects, for example, semiconductor wafers to form a thin film on the surfaces thereof or to perform a thermal diffusion. In an oxidation heat-treating apparatus, for example, of this type, water vapor and HCl gas produced by the combustion of hydrogen and oxygen within an external combustion apparatus is supplied into a reaction tube accommodating the objects by way of a gas supply piping made of, for example, quartz glass, and the gas which has completed the treatment on the objects is discharged from a gas exhaust piping connected to the reaction tube.
As a piping coupling or connection device for gas-tightly connecting the gas supply piping and gas exhaust piping to the heat-treating apparatus, there has been hitherto used a device of a type establishing a gas-tight connection by pressing confronting surfaces of a convex connecting element and a concave connecting element against each other using a pressing connection device.
In such type of piping connection device, however, a presser member may be unevenly abutted against the rear surface of the convex connecting element, for example, of the piping connection device if angularly set pipings are fastened together with the set angle therebetween left as it stands. Accordingly, the clamping of the pressing connection device may subject the pipings to a force which acts to eliminate the angle produced between the pipings and possibly damages the pipings. This imposes a restriction to the freedom of the piping connecting angle in the pipings and necessitates a highly accurate positioning technique upon the disposition of the piping connection device.